Advanced computers and data processing applications require high-speed couplings. Although the interconnections between boards and peripherals are usually performed electronically, fiber optic processing with a variety of fiber optic interconnects now are recognized as being inherently faster and more power efficient. As a consequence, optical switching has gained acceptance for a wide variety of data transfer operations including time division multiplexing.
Many approaches to providing optical crossbar switches have been attempted and some have used a parallel configuration. Another contemporary system relies on a matrix-like interface that requires that all but one common spatial light modulator is turned off while only a single common spatial light modulator is actuated to transfer a signal of interest. An example of such a system is shown in the article "Fiber Optic Crossbar Switch with Broadcast Capability" Optical Engineering, Vol 27, No 11, pp 955-959, November 1988. There is some evidence to suggest that the switching times may be unduly long, about 20 microseconds, because of the intervals required to switch-on and switch-off the light modulators. The real drawback of the matrix-like interface, however, is the excessive noise which is created when the unused spatial light modulators are turned off.
Thus, there is a continuing need in the state of the art for a high speed optical switching arrangement capable of reliable time division multiplexing applications that avoids an otherwise noisy parallel architecture such as those using spatial light modulators for the time division multiplexing of the optical information signals.